OK, I have my first 4K BD labelled HDR so I disassembled it and was looking at it with Media Tab to determine what some of the technical differences are between non HDR and HDR video, as compared to my existing library.

The first one was that the new video is 10 bit instead of 8 bit but further investigation has led me to believe that you can have 4k, non HDR video at 10 bit also.

Your 1 - 3 do not indicate HDR. 4:2:0 and limited range are standard for everything back to DVDs. Video with BT.2020 color primaries is usually HDR, but not always.

4 being non-constant and the presence of 5 - 7 all indicate it is encoded as HDR video. 5 - 7 is the "HDR metadata" you may have seen discussed.

Edit: I got confused on this point again.
BT.2020 non-constant would also be used for SDR BT.2020, it is BT.2020 constant that would most likely be HDR. I believe most HDR material out today is BT.2020 non-constant anyway. The constant or non-constant refers to linear or gamma like transfer functions, constant is linear.